Hybrid Atomistic and Coarse-Grained Molecular Dynamics Simulations of Polyethylene Glycol (PEG) Chains in Explicit Water for Designing Peg Based Biomaterials

Molecular dynamics (MD) is a well established technique to simulate the structure and dynamics of soft matter in general, and of biomolecular systems in particular. While simulations at the all-atom (AA) or united-atom (UA) level maintain atomistic chemical details, they are computationally intensive.  On the other hand coarse-grained (CG) models, in which several atoms are grouped together into effective interaction sites (CG beads), have been proven successful in achieving large length and time scales, while sacrificing atomistic level details. The in-silico design of polymeric biomaterials requires MD simulations that retain chemical detail for the essential biofunctional species and achieve large length and time scales pertinent to non-functional polymers. We are thus motivated to use hybrid atomistic – CG simulations, in which part of the system that is critical to the function of the biomaterial is represented at atomic resolution and the remaining part of the biomaterial that hosts the functional molecule is represented in coarse-grained level. Calculating the full atomistically detailed dynamics only in important regions of the system and reducing the complexity for the rest of the biomaterial can significantly reduce the computational cost and allow for optimal design of experimentally relevant length scale polymer based biomaterials. In this poster, we will present our recent efforts in building a hybrid simulation approach for poly(ethylene glycol) or PEG based biomaterials in aqueous medium for drug-delivery applications.